Han Solo actor Alden Ehrenreich reportedly watched his dad being stabbed to death by his uncle.

The Los Angeles native, who steps into Harrison Ford's shoes as the iconic Han Solo in Solo: A Star Wars Story, was just eight when the family tragedy is said to have unfolded.

Alden and his father Mark, aged 43, had gone to pick up his mentally ill uncle Edward to celebrate Hanukkah in December 1997.

But, Edward - who is said to have once been heavily into drugs - is believed to have suddenly pulled out a kitchen knife and stabbed his brother after being driven by voices in his head, according to The Sun .

The actor's dad drove to a nearby petrol station and called emergency services, but he later died in hospital as a result of his injuries.

Alden at the Cannes Film Festival on Tuesday (Image: Barcroft Media)

Alden and co-star Joonas Suotamo smile for pictures (Image: REUTERS)

Alden's uncle Nicholas Benedict, who was married to Mark and Edward's sister Ava, told the newspaper : “The last time I saw Alden was at the funeral for Mark, they had a get together at the house. It’s an incredibly tragic story.

“When Edward was younger he was heavily into LSD. He went overboard and freaked out - it screwed him up."

Nicholas went on: “He was crazy, he had schizophrenia, didn’t take his meds, then killed his brother.

Emilia Clarke and Alden Ehrenreich (Image: Getty)

The new film follows the Rogue One series - telling other stories in the Star Wars universe (Image: IAN LANGSDON/EPA)

"Apparently Edward was waiting for him with a kitchen knife.

“The devil told him to kill Mark or something like that. He was having hallucinations.”

Edward reportedly pleaded not guilty by reason of insanity and waived the right to a jury trial.

The movie got off to a rocky start (Image: AFP)

He was placed in a secure mental health insitution where he is thought to have died in 2005.

Alden, 28, got his first big break partly through his late dad, who worked as an accountant for Steven Spielberg.

The Oscar-winning director saw a video made by the aspiring actor, then 14, and recommended him to influencers in the industry.

He went on to land small roles in TV shows like CSI and Supernatural. Alden made his first feature-film debut in Francis Ford Coppola's Tetro in 2009.